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Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL?
...an work around it from within psql by executing the DDL statement conditionally:
SELECT 'CREATE DATABASE mydb'
WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = 'mydb')\gexec
The manual:
\gexec
Sends the current query buffer to the server, then treats each column of each row of the query's...
Multiline bash commands in makefile
...colon:
foo:
for i in `find`; \
do \
all="$$all $$i"; \
done; \
gcc $$all
But if you just want to take the whole list returned by the find invocation and pass it to gcc, you actually don't necessarily need a multiline command:
foo:
...
How do you crash a JVM?
...ught that you could do so by writing an infinite for-loop that would eventually use up all the memory.
27 Answers
...
Exclude a directory from git diff
...t diff previous_release current_release !(spec)
Saves you having to list all other things.
Or, shell-agnostic:
git diff previous_release current_release --name-only | grep -v '^spec/' \
| xargs git diff previous_release current_release --
You could wrap that up in a one-liner shell script ...
How can I tell if I'm running in 64-bit JVM or 32-bit JVM (from within a program)?
... 64 bit version is running, you'll get a message like:
java version "1.6.0_18"
Java(TM) SE Runtime Environment (build 1.6.0_18-b07)
Java HotSpot(TM) 64-Bit Server VM (build 16.0-b13, mixed mode)
A 32 bit version will show something similar to:
java version "1.6.0_41"
Java(TM) SE Runtime Environm...
TypeScript sorting an array
..., b) {
var ax = [], bx = [];
a.replace(/(\d+)|(\D+)/g, function (_, $1, $2) { ax.push([$1 || Infinity, $2 || ""]) });
b.replace(/(\d+)|(\D+)/g, function (_, $1, $2) { bx.push([$1 || Infinity, $2 || ""]) });
while (ax.length && bx.length) {
var an = ax.shift();
...
pandas resample documentation
...ffsets), and a section about resampling.
Note that there isn't a list of all the different how options, because it can be any NumPy array function and any function that is available via groupby dispatching can be passed to how by name.
...
How do I make a checkbox required on an ASP.NET form?
...ion for client side validation (using jQuery)...
function CheckBoxRequired_ClientValidate(sender, e)
{
e.IsValid = jQuery(".AcceptedAgreement input:checkbox").is(':checked');
}
code-behind for server side validation...
protected void CheckBoxRequired_ServerValidate(object sender, ServerValid...
Android Fragment lifecycle over orientation changes
...mit();
} else {
// do nothing - fragment is recreated automatically
}
Be warned though: problems will occur if you try and access Activity Views from inside the Fragment as the lifecycles will subtly change. (Getting Views from a parent Activity from a Fragment isn't easy).
...
ViewBag, ViewData and TempData
...
1)TempData
Allows you to store data that will survive for a redirect. Internally it uses the Session as backing store, after the redirect is made the data is automatically evicted. The pattern is the following:
public ActionResult Foo(...